In a cat or dog bite, which organism is most commonly involved?

In a cat or dog bite, which organism is most commonly involved?

• A. Streptococcus pyogenes
• B. Pasteurella multocida
• C. Bacteroides fragilis
• D. Clostridium tetani

Answer: (B)

Pasteurella multocida is the organism most commonly involved in cat or dog bites. This bacterium lives in the mouths of these animals, and when a bite breaches the skin, Pasteurella can be inoculated into the wound, often causing rapid local infection such as cellulitis within hours to a day and sometimes spreading to deeper structures like tendons or joints. Because Pasteurella is the usual culprit in these bites, empiric therapy for animal bite wounds is chosen to cover it, for example with amoxicillin-clavulanate. Other organisms listed can appear in bite wounds, but they are not the primary or most frequent pathogen in cat and dog bites: Streptococcus pyogenes is a possible skin pathogen but not the characteristic one for animal bites; Bacteroides fragilis is an anaerobe more linked to certain deep or gut-related infections; Clostridium tetani is a toxin-producing risk from contaminated wounds rather than the typical infecting organism.

Pasteurella multocida is the organism most commonly involved in cat or dog bites. This bacterium lives in the mouths of these animals, and when a bite breaches the skin, Pasteurella can be inoculated into the wound, often causing rapid local infection such as cellulitis within hours to a day and sometimes spreading to deeper structures like tendons or joints. Because Pasteurella is the usual culprit in these bites, empiric therapy for animal bite wounds is chosen to cover it, for example with amoxicillin-clavulanate. Other organisms listed can appear in bite wounds, but they are not the primary or most frequent pathogen in cat and dog bites: Streptococcus pyogenes is a possible skin pathogen but not the characteristic one for animal bites; Bacteroides fragilis is an anaerobe more linked to certain deep or gut-related infections; Clostridium tetani is a toxin-producing risk from contaminated wounds rather than the typical infecting organism.